Improving Old Barrels

[zymguy]

What was the accuracy expectation of each of these rifles in their prime ?
What's acceptable to shoot and enjoy ?

[Hannibal]

I'm sure they didn't keyhole at 25 yards for one .....

[Somebody]

Another option to retain the original chambering is to reline the barrel. It can be tricky to find liners that are not .22LR, but they do exist. Bore out, solder/epoxy the liner in place, recrown, and ream the leade.

Is it economical? Absolutely not, but the material cost is cheaper than barrel blanks.

[TheAbe]

What was the accuracy expectation of each of these rifles in their prime ?
What's acceptable to shoot and enjoy ?

For the M95, I’d be ok with 4MOA. I’m thinking if I can get a stable bullet, the accuracy will show itself.
Transmission fluid comes out today...we’ll see how it looks.

[TheAbe]

Before

After

It’s cleaner, shinier...but I’m even more convinced there isn’t any worthwhile rifling remaining. I will test it, but I think this one is heading for a re-sleeve, or rifling button...possibly both. Carcano will be next.

[TheAbe]

Took my Carcano apart today, covered the muzzle, and filled with automatic transmission fluid. Decided to do the same to my Krag while I was at it, since it was already apart.
I think there may be another issue with the Carcano besides the barrel, and that is the receiver. I get the idea it suffered a detonation or over-pressure round at one point, as when I got it the stock was cracked through the receiver, the receiver had a significant gap between it and the stock, and the bolt is very loose in the receiver. How loose? I noticed today that without a round, with the bolt closed I can wiggle the front of the bolt if I push at it, and the handle is loose (significantly) in its channel at all points when unlocked. I’ll check the performance once it goes through a week of AT fluid. I’ll note that spent brass is not noticeably larger than live rounds or spent brass from my other Carcano. Could a deformed receiver cause keyholing, even if the chamber and barrel are fine?

[john.k]

carcano is front locking.....any deformation is more likely from handling ,as in stacking in a big heap for surplus sale......where the stock got cracked ......also consider military rifles are fitted loose to work in mud ,dust ,and sand ........the Italians would have to cope with a lot of sand and dust in North Africa.

[TheAbe]

Here is the Carcano after a week of transmission fluid and a good cleaning. The patches actually come out clean now! It’s better than the KNIL, and has grooves that are more pronounced, even to the muzzle.

As for the lock, yes and the fact it’s front-locking is what has me concerned. I would think being front-locked, the front of the bolt should not move when the bolt is closed and locked, but perhaps that’s just when there isn’t a round chambered. I’ll try it with some empty brass as well.

As for next steps, there does appear to be some pitting and roughness...should I go for some valve grinding paste or perhaps a bit of fire lapping?

[TheAbe]

And instead of the bore, after reading some other threads here, I decided to use the grinding compound just to re-crown the Carcano. I think this will work...
Before:

After:

[TheAbe]

One month later, and I got to the range and tested a few projects including my long Carcano. The results I believe point to the barrel being worn, but capable with the right bullet design, and the crown DID need attention. 24 rounds total, all using .268” PPU bullets.
First 6 were the 139gr FMJ BT’s with an open base. Lots of keyholes here, and the worst indicator was 7 holes in the target with 6 rounds fired. I don’t want to think about how that happened, but the performance makes sense with what I’ve read about the Carcano design for long rifles with gain twist rifling. Rifle was designed to function with obturating bullets, and BT’s do not obturate well.


Next 6 rounds were with the 123gr SP bullet with a flat base. While the holes weren’t all perfectly round, they were almost all perfectly round, and so these were followed by 12 more rounds of the 123gr SP’s. All of these also had almost perfectly round holes. Shots were taken at 30-50 yards indoors. Im thinking these, because of their flat base, did obturate, caught the rifling, and were mostly stabilized. These would probably show even better stabilization at longer distance...I’ll try when I get the chance.
Previously the 123’s performed worse, and I’m thinking this was because the uneven crown was a controlling factor and had a greater impact on the lighter projectiles.

[Jim22]

a few years back i purchased Remington 510 barreled receiver that was damaged by sea water from hurricane Sandy - i purchased it for the receiver, which cleaned up with some filing + polishing - the bore was dark + no rifling visible let it set in scrap pile for months - one boring day i plugged it for the white vinegar treatment - after 3 days now can see rifling + it looks like it might be very shootable -

A detail: Household white vinegar is normally 3% acetic acid. Stronger vinegars are available if you look for them. Up to 30%. Don't know if this will help but maybe.

Jim

[303Guy]

This has been an interesting thread. I have a key-holing rifle. It's a Lee Enfield two-groove with a rager large bore and probably a worn throat. With some loads it would shoot some bullets nose first and some would go sideways. In this case, just reducing the load and using a slower powder did the trick. But what might be of some interest to you folks are the captured bullets. Some would show signs of just skipping the rifling then engaging while others just skipped. Reducing the charge would produce full rifling engagement.

Would you believe that this bore shoots cast? There is actually rifling in there. I fire-lapped out the rust. This is not the rifle in question though. The point is that very bad bores can sometimes still be made to shoot.



Back to the rifle in question.

These are 150gr Hornady's. The only reason why they hit near nose first is that the catch medium was inches from the muzzle. One can see the bore striations are straight so no spinning at all.


Here is a bullet that skipped at first then picked up the spin. It shows parallel striations then angled and the rifling grooves can be made out on it. There rifling impression can be made out if one looks carefully but what can't be seen in the photo is that in the rifling impression, the striations are not angled. I should try taking a better zoomed photo of it.


174gr fmj BT. These just skipped the rifling. Well actually, one didn't. I'd forgotten about that one.


This is a 110gr Hornady driven by 35gr H47895. Low pressure as the primer image indicates.

One can clearly see the full rifling impression.


What's interesting is that these bullets are very short in a very long throated rifle.

And the range test. I couldn't see the top of the foresight post too well so maybe the group could have been a bit rounder. This is only 25m so not stellar but promising once I've improved the front sight - which I've done but not tested.


And this is a 150 Hornady driven by a slower and lower pressure powder, BL-C(2). Not only that but it's a .308 bullet in a .305 bore.



Increasing the powder charge by 2 grains from 40 42 gr did this. Still nose first and I think it may have spun up a bit.



Skidded and keyholed 174gr fmj BT


One of these spun up and I'm guessing like the 150gr Hornady above.

This bore does shoot cast with full rifling engagement. It's not a terrible bore, just too large and too much jump for normal j-word loads. I did counter-bore it due to the bore condition near the muzzle.

[john.k]

Probably the safest way to remove bore rust is Evaporust ......Deck cleaner (oxalic acid ) is a lot cheaper and faster ,if you are in a hurry.........I would not use mineral acids ,with the exception of phosphoric acid .....iron buffered phosphoric acid will not dissolve steel ,and also leaves a protective coating......which is of little use in a gun bore..........however ,all that leaves a moonscape where the rust was ......IMHO ,the way to improve rusted bores is to recut to clean metal .........with a bit of fiddling around,its quite possible to recut the rifling ,then ream or hone the bore ......obviously ,it will all be oversize and require custom bullets.

[TheAbe]

Some fascinating information 303Guy. It’s seeming more and more like my next experiments should be with lighter loads, and see what happens. I will also try and get my hands on some 6.5 cast boolits. A lead melter and other equipment are in my near future.

I’m also considering having the KNIL re-chambered to .303 British or wildcatting to .270 Dutch or .280 Dutch. I have heard there is a gentleman by the name of Jom Kolb in my general area who might be willing and skilled to do such a re-chambering. Others have been strongly recommended on this forum, but I’d rather not have to ship anything.

As for evaporust, yes I have a gallon and it’s great stuff. I recently used it to clean up a rusty M1842, and the results were impressive. I think that would be a case where fire-lapping would be helpful after the rust was removed to smoothen the pits and the like, but if the rust wasn’t even it might just make things worse. I will try both lighter loads and patched bullets in the KNIL before re-chambering though.